title: Effects of feed time, organic loading and shock loads in anaerobic whey treatment by an AnSBBR with circulation.
abstract: The aim of this work was to investigate the effect of different feeding times (2, 4, and 6 h) and organic loading rates (3, 6 and 12 gCOD l(-1) day(-1)) on the performance of an anaerobic sequencing batch reactor containing immobilized biomass, as well as to verify the minimum amount of alkalinity that can be added to the influent. The reactor, in which mixing was achieved by recirculation of the liquid phase, was maintained at 30 +/- 1 degrees C, possessed 2.5 l reactional volume and treated 1.5 l cheese whey in 8-h cycles. Results showed that the effect of feeding time on reactor performance was more pronounced at higher values of organic loading rates (OLR). During operation at an OLR of 3 gCOD l(-1) day(-1), change in feeding time did not affect efficiency of organic matter removal from the reactor. At an OLR of 6 gCOD l(-1) day(-1), reactor efficiency improved in relation to the lower loading rate and tended to drop at longer feeding times. At an OLR of 12 gCOD l(-1) day(-1) the reactor showed to depend more on feeding time; higher feeding times resulted in a decrease in reactor efficiency. Under all conditions shock loads of 24 gCOD l(-1) day(-1) caused an increase in acids concentration in the effluent. However, despite this increase, the reactor regained stability readily and alkalinity supplied to the influent showed to be sufficient to maintain pH close to neutral during operation. Regardless of applied OLR, operation with feeding time of 2 h was which provided improved stability and rendered the process less susceptible to shock loads.
authors.affiliation: Departamento de Hidráulica e Saneamento, Escola de Engenharia de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense 400, CEP 13.566-590 São Carlos, SP, Brazil.
authors.forename: Roberto A
authors.initials: RA
authors.lastname: Bezerra
authors.forename: José A D
authors.initials: JA
authors.lastname: Rodrigues
authors.forename: Suzana M
authors.initials: SM
authors.lastname: Ratusznei
authors.forename: Marcelo
authors.initials: M
authors.lastname: Zaiat
authors.forename: Eugenio
authors.initials: E
authors.lastname: Foresti
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D019149:Bioreactors; D003611:Dairy Products; D005232:Fatty Acids, Volatile / Q000032:analysis; D005374:Filtration; D007220:Industrial Waste; D008697:Methane / Q000032:analysis; D009930:Organic Chemicals / Q000032:analysis*; D013997:Time Factors; D014865:Waste Disposal, Fluid
chemical_list: D005232:Fatty Acids, Volatile; D007220:Industrial Waste; D009930:Organic Chemicals; D008697:Methane